Optical filter, analytical instrument, optical apparatus, and method of manufacturing optical filter

ABSTRACT

An optical filter according to the invention includes: first and second substrates opposed to each other; first and second reflecting films provided to the first and second substrates; first and second bonding films provided to the first and second substrates; and first and second barrier films disposed on surfaces of the first and second reflecting films, wherein the first barrier film has a transmittance of ozone lower than a transmittance of ozone the first reflecting film has, and the second barrier film has a transmittance of ozone lower than a transmittance of ozone the second reflecting film has. Accordingly, the reflecting films are protected from ozone or ultraviolet radiation during the manufacturing process of the optical filter and thereby the optical filter characteristics is prevented from being deteriorated.

BACKGROUND

1. Technical Field

The present invention relates to an optical filter, an analyticalinstrument, an optical apparatus, a method of manufacturing the opticalfilter, and so on.

2. Related Art

There has been proposed an interference filter having a variabletransmission wavelength (JP-A-11-142752 (Document 1)). As shown in FIG.1 of Document 1, there are provided a pair of substrate held in parallelto each other, and a pair of reflecting films formed on the pair ofsubstrates so as to be opposed to each other and have a gap with aconstant distance. The light beam entering a gap between the pair ofreflecting films is multiply reflected on the same principle as aFabry-Perot interferometer, and the light component in the wavelengthband other than a specific wavelength band is canceled by interferencewhile only the light component in the specific wavelength band istransmitted. By making the gap between the pair of reflecting filmsvariable, the interference filter functions as a band-pass filter, andis called an etalon.

The pair of reflecting films can be formed of, for example, dielectricmultilayer films shown in JP-A-2009-134028 (Document 2), or metal filmsassuring high reflectance. Further, a pair of substrates arerespectively provided with bonding films, and each of the bonding filmsare bonded with the surfaces thereof activated (JP-A-2008-116669(Document 3), Japanese Patent No. 4337935 (Document 4)).

In the bonding method of Document 3, the pair of substrates are bondedvia the metal films (bonding films) provided respectively to the pair ofsubstrates by solid state bonding. However, the solid state bonding ofthe metal film is affected by the surface roughness, and lacks bondingreliability.

Incidentally, in the bonding method according to Document 4, bonding isperformed by activating the bonding film with ozone or ultravioletradiation. It has turned up that in the activation process of thebonding film a pair of reflecting films formed of metal films ordielectric multilayer films might be damaged to be changed in quality ordeteriorated, and thus the reflectance thereof might be degraded. Thepair of reflecting films might be negatively affected by ozone orultraviolet radiation depending also on the environment in which theoptical filter is disposed.

SUMMARY

An advantage of some aspects of the invention is to provide an opticalfilter, an analytical instrument, an optical apparatus, and a method ofmanufacturing the optical filter each capable of protecting the pair ofreflecting films from ozone or ultraviolet radiation in themanufacturing process or in actual use of the optical filter, therebypreventing the optical filter characteristics from being deteriorated.

1. According to an aspect of the invention, there is provided a methodof manufacturing an optical filter including the steps of (p) providinga first bonding film to a first substrate provided with a firstreflecting film, (q) providing a second bonding film to a secondsubstrate provided with a second reflecting film, (r) forming a firstbarrier film so as to cover a surface of the first reflecting film ofthe first substrate, (s) forming a second barrier film so as to cover asurface of the second reflecting film of the second substrate, (e)providing activation energy to each of the first and second bondingfilms using one of ozone and an ultraviolet ray, and (f) bonding thefirst and second bonding films activated to thereby bond the first andsecond substrates to each other, wherein step (r) is performed prior toproviding the activation energy to the first bonding film in step (e),and step (s) is performed prior to providing the activation energy tothe second bonding film in step (e).

According to the aspect of the invention, the first and second barrierfilms can prevent ozone or an ultraviolet ray from entering the firstand second reflecting films when providing the activation energy to thefirst and second bonding films with ozone or an ultraviolet ray.Therefore, it is possible to prevent the first and second reflectingfilms from being changed in quality or deteriorated due to ozone or anultraviolet ray, thereby preventing the reflectance of the first andsecond reflecting films from decreasing.

2. According to another aspect of the invention, in the optical filteraccording to the above aspect of the invention, it is possible that thefirst barrier film and the first bonding film are deposited with thesame material in the same process, and the second barrier film and thesecond bonding film are deposited with the same material in the sameprocess.

According to this configuration, the process for depositing the firstbarrier film and the deposition process of the first bonding film can beperformed in the same process, and the process for depositing the secondbarrier film and the deposition process of the second bonding film canbe performed in the same process. Therefore, there is no need toadditionally provide the process for depositing the first and secondbarrier films. The first and second barrier films and the first andsecond bonding films manufactured by any method can be adopted, and thefirst and second barrier films and the first and second bonding filmscan be manufactured by, for example, a plasma polymerization method,various vapor deposition methods including a CVD method and a PVDmethod, or various liquid phase deposition methods. Among these methods,those manufactured by a plasma polymerization method are preferable.According to the plasma polymerization method, a dense and homogeneousfilm can efficiently be manufactured.

3. According to still another aspect of the invention, in the opticalfilter according to the above aspect of the invention, it is possiblethat the first and second bonding films and the first and second barrierfilms are each formed including an Si skeleton having a siloxane bond,and an elimination group connected to the Si skeleton, step (e) includes(e1) forming a dangling bond by eliminating the elimination group fromthe Si skeleton in each of the first and second bonding films, and step(f) includes (f1) bonding the dangling bonds of the respective first andsecond bonding films, which are activated, to each other.

According to this configuration, in the bonding process of the first andsecond bonding films, the dangling bonds of the respective first andsecond bonding films, which are activated, are bonded to each other,thus the first and second substrates can be bonded solidly to eachother. The first and second barrier films are each formed including anSi skeleton having a siloxane bond (Si—O—Si), and an elimination groupconnected to the Si skeleton, Since the passing route of the gas isblocked by the siloxane bond, a high gas barrier property with respectto ozone gas or the like can be obtained. Further, since the first andsecond barrier films do not have the dangling bond, the first and secondbarrier films become to have characteristics of low in reactivity andhard to be oxidized or sulfurized. Further, the siloxane bond absorbslight with a wavelength equal to or shorter than 200 nm including thewavelength band of an ultraviolet ray similarly to the case of SiO₂films. If the first and second barrier films absorb an ultraviolet ray,the first and second barrier films are exited to rise in the energystate, but are not changed in the state because the bond energy of thesiloxane bond is greater than the excitation energy due to theultraviolet radiation.

4. According to yet another aspect of the invention, there is providedan optical filter including a first substrate, a second substrateopposed to the first substrate, a first reflecting film provided to thefirst substrate, a second reflecting film provided to the secondsubstrate and opposed to the first reflecting film, a first bonding filmprovided to the first substrate, a second bonding film provided to thesecond substrate, bonded to the first bonding film so as to provide acertain gap between the first and second reflecting films, a firstbarrier film formed on a surface of the first reflecting film, and asecond barrier film formed on a surface of the second reflecting film,wherein the first barrier film has transmittance of ozone or anultraviolet ray lower than that of the first reflecting film, and thesecond barrier film has transmittance of ozone or an ultraviolet raylower than that of the second reflecting film.

The optical filter can prevent ozone of an ultraviolet ray from enteringthe first and second reflecting films with the first and second barrierfilms. Therefore, it is possible to prevent the first and secondreflecting films from being changed in quality or deteriorated due toozone or an ultraviolet ray, thereby preventing the reflectance of thefirst and second reflecting films from decreasing. Therefore, it ispossible to prevent the first and second reflecting films from beingchanged in quality or deteriorated in actual use in which the opticalfilter is exposed to an ultraviolet ray or ozone atmosphere, or in themanufacturing process of the optical filter in which the activationenergy is provided to the first and second bonding films with ozone oran ultraviolet ray.

5. According to still yet another aspect of the invention, in theoptical filter according to the above aspect of the invention, it ispossible that the first barrier film has a sulfurization property lowerthan a sulfurization property of the first reflecting film, and thesecond barrier film has a sulfurization property lower than asulfurization property of the second reflecting film.

According to the configuration described above, it is possible toprevent the first and second reflecting films from being sulfurized byhydrogen sulfide or the like to be changed in quality or deteriorated.

6. According to further another aspect of the invention, in the opticalfilter according to the above aspect of the invention, it is possiblethat the first and second barrier films are each a plasma-polymerizedfilm formed simultaneously with the first and second bonding filmsdeposited by a plasma polymerization method. According to the plasmapolymerization method, since the first and second barrier films and thefirst and second bonding films can be made dense and homogeneous films,and moreover, low cost can be maintained because no additionaldeposition process is required.

7. According to still further another aspect of the invention, in theoptical filter according to the above aspect of the invention, it ispossible that the first and second bonding films and the first andsecond barrier films include an Si skeleton having a siloxane bond, andan elimination group connected to the Si skeleton in a plasmapolymerization process, and the first and second bonding films arebonded to each other by bonding dangling bonds to each other, thedangling bond being formed by eliminating the elimination group from theSi skeleton due to activation energy.

Since the dangling bonds caused by activation are bonded to each otherin the first and second bonding films, the first and second substratescan solidly be bonded to each other. On the other hand, the first andsecond barrier films each have a high gas barrier property due to thesiloxane bond blocking the passing route to the gas, and have lowreactivity because no dangling bond exists therein, and further, thesiloxane bond can absorb an ultraviolet ray.

8. According to yet further another aspect of the invention, ananalytical instrument including any one of the optical filters describedabove is defined. As an analytical instrument of this kind, the lightbeam reflected, absorbed, transmitted, or emitted by the analysis objectis made to input a variable wavelength optical filter, the light beamswith respective wavelengths transmitted through the optical filter arereceived by the light receiving element, and the signal from the lightreceiving element is operated by an arithmetic circuit, therebymeasuring the intensity of the light beams with the respectivewavelength, for example, thus the color, mixture component in the gas,and so on can be analyzed.

9. According to still yet further another aspect of the invention, anoptical apparatus including any one of the optical filters describedabove is defined. As an optical apparatus of this kind, there can becited a transmitter of an optical multiplexing communication system suchas an optical code division multiplexing (OCDM) transmitter or awavelength division multiplexing (WDM) transmitter. In the WDM, thechannels are discriminated by the wavelength of the optical pulseconstituting the optical pulse signals. Although in the OCDM thechannels are discriminated by pattern matching of encoded optical pulsesignals, the optical pulses constituting the optical pulse signalsinclude light components with respective wavelengths different from eachother. Therefore, in the transmitter of the optical multiplexingcommunication system, it is required to use light beams with a pluralityof wavelengths, and by using the optical filter according to any one ofthe above aspects of the invention, a plurality of light beams withrespective wavelengths can be obtained from a light beam emitted from asingle light source.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a vertical cross-sectional view of an overall optical filteraccording to an embodiment of the invention.

FIG. 2 is a schematic perspective view of the optical filer shown inFIG. 1 with a part thereof cut.

FIG. 3 is a schematic diagram schematically showing the structure of aplasma-polymerized film (each of first and second barrier films) notprovided with activation energy.

FIG. 4 is a schematic diagram schematically showing the structure of aplasma-polymerized film provided with the activation energy.

FIGS. 5A through 5C are diagrams respectively showing first throughthird manufacturing steps of a first substrate.

FIGS. 6A through 6C are diagrams respectively showing fourth throughsixth manufacturing steps of the first substrate.

FIGS. 7A through 7D are diagrams respectively showing first throughfourth manufacturing steps of a second substrate.

FIGS. 8A through 8D are diagrams respectively showing fifth througheighth manufacturing steps of the second substrate.

FIG. 9 is a diagram showing a process of providing the activation energyto the first and second bonding films not activated.

FIG. 10 is a diagram showing a bonding process of the first and secondsubstrates.

FIG. 11 is a block diagram of an analytical instrument according tostill another embodiment of the invention.

FIG. 12 is a flowchart showing a spectral measurement operation in theinstrument shown in FIG. 11.

FIG. 13 is a block diagram of an optical apparatus according to stillanother embodiment of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, some preferred embodiments of the invention will bedescribed in detail. It should be noted that the present embodimentexplained below does not unreasonably limit the content of the inventionas set forth in the appended claims, and all of the constituents setforth in the present embodiments are not necessarily essential as meansof the invention for solving the problems.

1. General Description of Optical Filter Structure

FIG. 1 is a vertical cross-sectional view of the whole of an opticalfilter 10 according to the present embodiment, and FIG. 2 is a schematicperspective view of the optical filter 10 with a part thereof cut. Theoptical filter 10 shown in FIGS. 1 and 2 includes a first substrate 20and a second substrate 30 opposed to the first substrate 20. Although inthe present embodiment it is assumed that the first substrate 20 is afixed substrate or base substrate, and the second substrate 30 is amovable substrate or diaphragm substrate, it is sufficient that eitherone or both of the substrates are movable.

The first and second substrates 20, 30 are each made of various types ofglass such as soda glass, crystalline glass, quartz glass, lead glass,potassium glass, borosilicate glass, or alkali-free glass, a quartzcrystal, or the like. In the present embodiment, the constituentmaterial of each of the substrates 20, 30 is synthetic silica glass.Each of the first and second substrates 20, 30 is formed to have asquare shape, for example 10 mm on a side, and the greatest diameter ofthe portion functioning as a circular diaphragm is, for example, 5 mm.

The first substrate 20 has an opposed surface 20A opposed to the secondsubstrate 30, and the second substrate 30 has an opposed surface 30Aopposed to the first substrate 20. In the present embodiment, theopposed surface 20A is provided with, for example, first through fourthopposed surfaces 20A1 through 20A4 having respective heights differentfrom each other, while the opposed surface 30A is formed as a flatsurface.

There are formed a first reflecting film 40 on the first opposed surface20A1 of the first substrate 20, a first electrode 60 on the secondopposed substrate 20A2, a first bonding film 100 on the third opposedsurface 20A3, and a first wiring layer and a relay wiring layer 62Bisolated from each other on the fourth opposed surface 20A4,respectively. On the opposed surface 30A of the second substrate 30there are formed a second reflecting film 50 opposed to the firstreflecting film 40, a second electrode 70 opposed to the first electrode60, a second bonding film 110 opposed to the first bonding film 100, andthe second wiring layer 72 opposed to the relay wiring layer 62B.Further, a first barrier film 120 is formed on a surface of the firstreflecting film 40, and a second barrier film 130 is formed on a surfaceof the second reflecting film 50.

It should be noted that as shown in FIG. 1 in the outer peripheralportions of the first and second substrates 20, 30, there are formed afirst electrode lead-out section 64 for connecting the first electrode60 to an external device, and a second electrode lead-out section 74 forconnecting the second electrode 70 to an external device. In the firstelectrode lead-out section 64, the first wiring layer 62 electricallyconnected to the first electrode 60 is connected to a first lead wire68. In the second electrode lead-out section 74, the second wiring layer72 provided to the second substrate 30 is electrically connected to therelay wiring layer 62B on the side of the first substrate 20 via aconductive member 66 such as solder, and a second lead wire 76 isconnected to the relay wiring layer 62B.

The first substrate 20 as the base substrate is formed to have the firstthrough fourth opposed surfaces 20A1 through 20A4 by etching a glasssubstrate formed to have a thickness of, for example, 500 μm. The firstsubstrate 20 is provided with a first reflecting film 40 having, forexample, a circular shape formed on a first opposed surface 20A1 locatedat a central portion out of the opposed surface 20A opposed to thesecond substrate 30. The second substrate 30 is provided with adiaphragm section 32 formed to have a small wall-thickness and, forexample, a ring-like shape, and is further provided with a reflectingfilm support section 34 having a larger wall-thickness formed at acentral portion thereof as shown in FIG. 2 by etching a glass substrateformed to have a thickness of, for example, 200 μm. The second substrate30 is provided with a second reflecting film 50 having, for example, acircular shape, and opposed to the first reflecting film 40, formed onthe opposed surface 30A opposed to the first substrate 20 at a positionof the reflecting film support section 34.

The first and second reflecting films 40, 50 are each formed to have,for example, a circular shape with a diameter of about 3 mm. The firstand second reflecting films 40, 50 are formed to have the same thicknessusing the same material. The first and second reflecting films 40, 50are each deposited by a sputtering method or an evaporation method usinga material such as Ag, Al, SiO₂, TiO₂, or Ta₂O₅ as a single layer or astacked layer, and are each formed to have a metal layer made of Ag, Al,or the like as the outermost surface. It is also possible to form eachof the first and second reflecting films 40, 50 as a single layer, andit is also possible to form it as a dielectric multilayer film obtainedby alternately stacking, for example, TiO₂ and SiO₂.

Further, it is possible to form antireflection films (AR) not shown onthe respective surfaces of the first and second substrates 20, 30 on theopposite side to the opposed surfaces 20A1, 20A2, and 30A thereof atpositions corresponding to the first and second reflecting films 40, 50.The antireflection films are each formed by alternately stacking lowrefractive index films and high refractive index films, and decrease thereflectance to the visible light on the interfaces of the first andsecond substrates 20, 30 while increasing the transmittance thereof.

The first and second reflecting films 40, 50 respectively provided withthe first and second barrier films 120, 130 are disposed so as to beopposed to each other via a first gap G1 shown in FIG. 1. It should benoted that although in the present embodiment it is assumed that thefirst reflecting film 40 is a fixed mirror and the second reflectingfilm 50 is a movable mirror, it is possible to make either one or bothof the first and second reflecting films 40, 50 movable in accordancewith the configuration of the first and second substrates 20, 30described above.

The second opposed surface 20A2, which is located on the periphery ofthe first reflecting film 40 and on the periphery of the first opposedsurface 20A1 of the first substrate 20 in the plan view, is providedwith the first electrode 60. Similarly, the opposed surface 30A of thesecond substrate 30 is provided with the second electrode 70 so as to beopposed to the first electrode 60. The first electrode 60 and the secondelectrode 70 are each formed to have, for example, a ring-like shape asshown in FIG. 2, and are arranged so as opposed to each other via asecond gap G2 shown in FIG. 1. It should be noted that the surfaces ofthe first and second electrodes 60, 70 can be covered by an insulatingfilm.

In the present embodiment, the opposed surface 20A of the firstsubstrate 20 has the first opposed surface 20A1 provided with the firstreflecting film 40, and the second opposed surface 20A2 arranged on theperiphery of the first opposed surface 20A1 in a plan view, and providedwith the first electrode 60. Although the first opposed surface 20A1 andthe second opposed surface 20A2 can be coplanar with each other, in thepresent embodiment there is a step between the first opposed surface20A1 and the second opposed surface 20A2, and the second opposed surface20A2 is placed nearer to the second substrate 30 than the first opposedsurface 20A1. Thus, the relationship of (first gap G1)>(second gap G2)becomes true. This is not a limitation, but the relationship of (firstgap G1)<(second gap G2) can also be adopted.

The first and second electrodes 60, 70 are formed to have the samethickness using the same material. In the present embodiment, the firstand second electrodes 60, 70 are each deposited by a sputtering methodto have a thickness of, for example, about 0.1 μm using lighttransmissive indium tin oxide (ITO) doped with tin oxide as an impurity.Therefore, it results that the gap of the actuator section is determinedin accordance with the depth of a recessed section, the thickness of theelectrodes, and the thickness of the bonding films. Here, the materialof the electrodes is not limited to ITO, but can be metal such as gold.However, in the present embodiment ITO is used for the reason thatwhether or not discharge occurs is easily checked because of thetransparency thereof.

Here, the pair of electrodes, namely the first and second electrodes 60,70 function as a gap variable drive section 80 for varying the dimensionof the first gap G1 between the first and second reflecting films 40,50. The gap variable drive section 80 of the present embodiment is anelectrostatic actuator. The electrostatic actuator 80 is provided withan electrical potential difference between the first and secondelectrodes 60, 70 as the pair of electrodes to cause electrostaticattractive force for varying the dimension of the second gap G2 betweenthe first and second electrodes 60, 70 as the pair of electrodes, andthus moving the second substrate 30 relatively to the first substrate20, thereby varying the dimension of the first gap G1 between the firstand second reflecting films 40, 50. It should be noted that the gapvariable drive section 80 is not limited to the electrostatic actuator,but can be replaced with a piezoelectric element or the like.

2. Bonding Films and Barrier Films

The third opposed surface 20A3, which is located on the periphery of thefirst electrode 60 and on the periphery of the second opposed surface20A2 of the first substrate 20 in the plan view, is provided with thefirst bonding film 100. Similarly, the opposed surface 30A of the secondsubstrate 30 is provided with the second bonding film 110 so as to beopposed to the first bonding film 100.

The first barrier film 120 is formed to cover the surface of the firstreflecting film 40, using a material having the transmission of ozone orultraviolet radiation lower than that of the first reflecting film 40.The second barrier film 130 is formed to cover the surface of the secondreflecting film 50, using a material having the transmission of ozone orultraviolet radiation lower than that of the second reflecting film 50.

Here, the first and second bonding films 100, 110 can be bonded afterthe activation energy is provided by ozone of ultraviolet irradiation.Moreover, the first barrier film 120 can be formed prior to providingthe activation energy at least to the first bonding film 100, and thesecond barrier film 130 can be formed prior to providing the activationenergy at least to the second bonding film 110. According to thisprocess, it is possible to prevent ozone or an ultraviolet ray fromentering the first reflecting film 40 or the second reflecting film 50when providing the activation energy to the first bonding film 100 orthe second bonding film 110 by ozone or ultraviolet irradiation. Asdescribed above, the first and second reflecting films 40, 50 can beprevented from being reduced in reflectance due to the change in qualityor deterioration caused by being exposed to ozone or ultravioletradiation.

In some cases, the first and second reflecting films 40, 50 are formedusing a metal film such as an Ag film or an Al film as a particularlyhigh reflectance film. These metal films have low environmentalresistances, and might be altered to metal oxide films by, for example,being exposed to ozone of oxygen plasma or to ozone generated byultraviolet irradiation. Further, when the metal films are irradiatedwith ultraviolet ray, the metal atoms are ionized, and become easy tooxidize or sulfurize due to a photoelectric effect. Incidentally, evenif dielectric multilayer films are used as the first and secondreflecting films 40, 50, there is a possibility that the dielectricmultilayer films are damaged physically or excessively oxidized tothereby be altered in film quality although the dielectric multilayerfilms are composed of metal oxide films or the like, and are originallyhard to react with oxygen. In the present embodiment, such alternationand deterioration of the first and second reflecting films 40, 50 asdescribed above can be prevented using the first and second barrierfilms 120, 130.

It should be noted that the formation timing of the first and secondbarrier films 120, 130 is not necessarily limited to the period beforethe activation energy provision process. This is because the first andsecond reflecting films can be protected from ozone and ultravioletradiation even in the case in which the optical filter 10 isincorporated in an apparatus using an ultraviolet ray. From theviewpoint of protecting the first and second reflecting films 40, 50 fora long period of time taking the actual use of the optical filter 10into consideration as described above, the first and second barrierfilms 120, 130 preferably have film characteristics high in theenvironmental resistance in addition to the ozone resistance or theultraviolet resistance. In particular, the first and second barrierfilms 120, 130 are preferably provided with other properties such as lowreactivity (sulfurization property) with hydrogen sulfide (H₂S) or thelike, low reactivity (halogenation property) with halogen series, or ahigh moisture resistance in view of the reliability as a commercialproduct in comparison with the first and second reflecting films 40, 50.

Here, the first and second bonding films 100, 110 can be formed asplasma-polymerized films deposited by a plasma polymerization method. Onthis occasion, the first and second barrier films 120, 130 can be formedas plasma-polymerized films formed simultaneously with the first andsecond bonding films 100, 110. According to this procedure, thedeposition process for the first and second barrier films 120, 130 canalso be used as the deposition process for the first and second bondingfilms 100, 110, and no additional manufacturing process is required.Therefore, cost reduction of the optical filter 10 can be maintained.

Each of the first and second bonding films 100, 110, and the first andsecond barrier films 120, 130 can include an Si skeleton having asiloxane bond (Si—O—Si) and an elimination group bonded to the Siskeleton in the plasma polymerization.

FIG. 3 schematically shows a structure of such a plasma-polymerizedfilm. FIG. 3 shows the structure of the first and second barrier films120, 130 formed of the plasma-polymerized films, which is the same asthe structure of the first and second bonding films 100, 110 not yetprovided with the activation energy formed of the plasma-polymerizedfilms. Therefore, although the explanation will hereinafter be presentedwith reference to FIG. 3 assuming the first and second barrier films120, 130, the explanation can also be applied to the first and secondbonding films 100A, 110A (see FIGS. 6C and 8D described later)corresponding to the first and second bonding films 100, 110 notprovided with the activation energy.

Further, FIG. 4 shows a structure of the first and second bonding films100B, 110B (see FIG. 9 described later) obtained by activating the firstand second bonding films 100A, 110A, which are not provided with theactivation energy and have the structure shown in FIG. 3, with theactivation energy.

The first and second barrier films 120, 130 shown in FIG. 3, and thefirst and second bonding films 100B, 110B activated shown in FIG. 4 eachinclude the siloxane bond (Si—O—Si) 302, and have the Si skeleton 301with, for example, a random atomic arrangement. The first and secondbarrier films 120, 130 shown in FIG. 3 have the elimination group 303bonded to the Si skeleton 301. In contrast, the first and second bondingfilms 100B, 110B activated shown in FIG. 4 have active hands (danglingbond) 304 formed by eliminating the elimination groups 303 from the Siskeleton 301. It should be noted that the active hands 304 include bonds(hereinafter also referred to as “dangling bonds”) not terminated andthose obtained by terminating the dangling bonds with hydroxyl groups(OH groups) in the Si skeleton 301.

The first and second barrier films 120, 130 and the first and secondbonding films 100B, 110B activated each become a solid film hard to bedeformed under the influence of the Si skeleton 301 including thesiloxane bond 302 and having a random atomic arrangement. It isconceivable that this is because a defect such as dislocation or shiftin the grain boundary is hardly generated since the crystallinity of theSi skeleton 301 is reduced. Therefore, the film itself becomes to havehigh bonding strength, high chemical resistance, and high dimensionaccuracy, and in the first and second bonding films 100, 110 and thefirst and second barrier films 120, 130 obtained finally, those havinghigh chemical resistance and high dimension accuracy can be obtained,and in the first and second barrier films 120, 130 high bonding strengthcan be obtained.

The characteristics of the first and second barrier films 120, 130described above can also be explained from the structure having the Siskeleton 301 including the siloxane bond (Si—O—Si) 302, and theelimination group 303 bonded to the Si skeleton 301. Specifically, thepassing route of the gas is blocked by the siloxane bond (Si—O—Si) 302,and thus the high gas-barrier property can be obtained. Further, sincethe first and second barrier films 120, 130 do not have the danglingbond 304 shown in FIG. 4, the first and second barrier films 120, 130become to have characteristics of low in reactivity and hard to beoxidized or sulfurized. Further, the siloxane bond (Si—O—Si) 302 absorbslight with a wavelength equal to or shorter than 200 nm including thewavelength band of an ultraviolet ray similarly to the case of SiO₂. Ifthe first and second barrier films 120, 130 absorb an ultraviolet ray,the first and second barrier films 120, 130 are exited to rise in theenergy state, but are not changed in the state because the bond energyof the siloxane bond (Si—O—Si) 302 is greater than the excitation energydue to the ultraviolet radiation.

When the activation energy is provided to the first and second bondingfilms 100A, 110A not yet provided with the activation energy having thestructure shown in FIG. 3, the elimination groups 303 are eliminatedfrom the Si skeleton 301, and as shown in FIG. 4, the active hands 304are generated on the surface of or inside the first and second bondingfilms 100B, 110B thus activated. Thus, an adhesion property is developedon the surfaces of the first and second bonding films 100B, 110Bactivated, and the dangling bonds out of the active hands 304 of thefirst and second bonding films 100B, 110B are bonded to each other,thereby obtaining the first and second bonding films 100, 110 bonded toeach other shown in FIG. 1. The first substrate 20 provided with thefirst bonding film 100B activated becomes capable of being bonded to thesecond substrate 30, which is provided with the second bonding film 110Bactivated, solidly, efficiently, and with high dimensional accuracy.

The first and second barrier films 120, 130 and the first and secondbonding films 100B, 110B activated each become a solid member withoutfluidity. Therefore, the thickness and shape of the film hardly changecompared to a liquid or mucous adhesive used in the related art. Thus,the dimensional accuracy of the films can be dramatically improvedcompared to the related art. Further, since the time necessary forcuring the adhesive becomes unnecessary, solid bonding can be achievedin a short period of time.

In the first and second barrier films 120, 130 and the first and secondbonding films 100, 110, in particular, a sum of the content rate of Siatoms and the content rate of O atoms out of the atoms obtained byeliminating the H atoms from the total atoms constituting the film ispreferably in a range of 10 through 90 atomic percent, and morepreferably in a range of 20 through 80 atomic percent. If the Si atomsand the O atoms are included at the content rate within this range, inthe first and second barrier films 120, 130 and the first and secondbonding films 100, 110, the Si atoms and the O atoms form a solidnetwork, and the films themselves become solid. Further, it results thatthe first and second bonding films 100, 110 can bond the first andsecond substrates 20, 30 to each other with high bonding strength.

Further, the abundance ratio between the Si atoms and the O atoms in thefirst and second barrier films 120, 130 and the first and second bondingfilms 100, 110 is preferably in a range of 3:7 through 7:3, and morepreferably in a range of 4:6 through 6:4. By setting the abundance ratiobetween the Si atoms and the O atoms to fall within this range, thestability of the films can be improved. According also to thisarrangement, it results that the first and second bonding films 100, 110can bond the first and second substrates 20, 30 to each other with highbonding strength.

It should be noted that the crystallinity of the Si skeleton 301 in thefirst and second barrier films 120, 130 and the first and second bondingfilms 100, 110 is preferably equal to or lower than 45%, and morepreferably equal to or lower than 40%. Thus, the Si skeleton 301 becomesto include sufficiently random atomic arrangement. Therefore, thecharacteristics of the Si skeleton 301 described above becomeactualized.

Further, the first and second barrier films 120, 130 and the first andsecond bonding films 100, 110 preferably include an Si—H bond in thestructures thereof. The Si—H bond is generated in the polymericsubstance when the polymerization reaction of silane is performed by theplasma polymerization method, and it is conceivable that the Si—H bondhinders the regular generation of the siloxane bond on this occasion.Therefore, it results that the siloxane bond is formed so as to keep offthe Si—H bond to thereby degrade the regularity of the atomicarrangement of the Si skeleton 301. In such a manner as described above,according to the plasma polymerization method, the Si skeleton 301 withlow crystallinity can efficiently be formed.

On the other hand, it is not necessarily true that the higher thecontent ratio of the Si—H bond in the first and second barrier films120, 130 and the first and second bonding films 100, 110 is, the lowerthe crystallinity becomes. Specifically, assuming that the intensity ofthe peak attributing to the siloxane bond is 1 in the infrared lightabsorption spectrum, the intensity of the peak attributing to the Si—Hbond is preferably in a range of 0.001 through 0.2, further preferablyin a range of 0.002 through 0.05, and still further preferably in arange of 0.005 through 0.02. By setting the ratio of the Si—H bond tothe siloxane bond to be within the range, the atomic arrangement becomesrelatively the most random. Therefore, in the case in which the peakintensity of the Si—H bond exists within this range with respect to thepeak intensity of the siloxane bond, the first and second barrier films120, 130 and the first and second bonding films 100, 110 becomeparticularly superior in chemical resistance and dimensional accuracy,and the first and second bonding films 100, 110 also become superior inbonding strength.

Further, the elimination group 303 bonded to the Si skeleton 301 iseliminated from the Si skeleton 301 to thereby act so as to generate theactive hands in the bonding films 100, 110. Therefore, the eliminationgroup 303 needs to be evenly eliminated with relative ease in responseto the provision of the energy but to surely be bonded to the Siskeleton 301 so as not to be eliminated when no energy is provided.

From such a viewpoint, as the elimination group 303 there is preferablyused what is constituted with at least one species selected from thegroup consisting of H atom, B atom, C atom, N atom, O atom, P atom, Satom, and halogen series atom, and an atomic group including either oneof these atoms and arranging these atoms so as to be bonded to the Siskeleton 301. Such an elimination group 303 is relatively superior inselectivity of bond/elimination in accordance with provision of theenergy. Therefore, such an elimination group 303 becomes to sufficientlysatisfy the requirement described above, and it becomes possible to makethe adhesion property of the first and second bonding films 100, 110further enhanced.

It should be noted that as the atomic group (group) having the atomsarranged so as to be bonded to the Si skeleton 301, there can be cited,for example, an alkyl group such as a methyl group or an ethyl group, analkenyl group such as a vinyl group or an allyl group, an aldehydegroup, a ketone group, a carboxyl group, an amino group, an amide group,a nitro group, an alkyl halide group, mercapto group, a sulfonate group,a cyano group, or an isocyanate group.

Among these groups, the alkyl group is particularly preferable for theelimination group 303. Since the alkyl group has high chemicalstability, the first and second barrier films 120, 130 containing thealkyl groups become superior in a barrier property such as anenvironmental resistance or a chemical resistance.

Here, in the case in which the elimination group 303 is the methyl group(—CH₃), the preferable content ratio thereof is defined as follows inaccordance with the peak intensity in the infrared light absorptionspectrum. Specifically, assuming that the intensity of the peakattributing to the siloxane bond is 1 in the infrared light absorptionspectrum, the intensity of the peak attributing to the methyl group ispreferably in a range of 0.05 through 0.45, further preferably in arange of 0.1 through 0.4, and still further preferably in a range of 0.2through 0.3. By setting the ratio of the peak intensity of the methylgroup to the peak intensity of the siloxane bond to be within the range,the necessary and sufficient number of active hands 304 are generated inthe first and second bonding films 100B, 110B activated while preventingthe methyl groups from unnecessarily hindering the generation of thesiloxane bond. Therefore, a sufficient adhesion property is provided tothe first and second bonding films 100B, 110B activated. Further, thesufficient barrier properties due to the methyl group, such as theenvironmental resistance and the chemical resistance develop in thefirst and second barrier films 120, 130.

As a constituent material of the first and second barrier films 120, 130and the first and second bonding films 100, 110 having thecharacteristics described above, a polymeric material including thesiloxane bond such as polyorganosiloxane can be cited. The filmconstituted with polyorganosiloxane itself has superior mechanicalcharacteristics. Further, it exhibits a particularly superior adhesionproperty with respect to various types of materials. Therefore, thefirst and second bonding films 100, 110 constituted withpolyorganosiloxane exhibit particularly strong adhesion force, and as aresult, are capable of solidly bonding the first and second substrates20, 30 to each other.

Further, although polyorganosiloxane normally exhibits water repellency(non-adherent property), by providing the activation energy, organicgroups can easily be eliminated to change itself to be hydrophilic tothereby develop an adherence property. There is obtained an advantagethat the control between the non-adherent property and the adherenceproperty can easily and surely be performed.

It should be noted that the water repellency (the non-adherent property)is an action mainly due to the alkyl groups contained inpolyorganosiloxane. Therefore, the first and second bonding films 100A,110A not activated and constituted with polyorganosiloxane also has anadvantage of developing an adherence property on the surface thereof,and at the same time, obtaining the action and effect due to the alkylgroup described above in response to the provision of the activationenergy. Therefore, the first and second barrier films 120, 130 and thefirst and second bonding films 100, 110 are made superior inenvironmental resistance and chemical resistance.

Further, among polyorganosiloxane, those consisting primarily of apolymer of octamethyltrisiloxane are particularly preferable. The firstand second bonding films 100, 110 consisting primarily of a polymer ofoctamethyltrisiloxane are particularly superior in adherence property,and therefore, particularly preferable. Further, the material consistingprimarily of octamethyltrisiloxane takes a liquid format normaltemperature, and has appropriate viscosity, and therefore, provides anadvantage of easy handling.

Further, the average thickness of the first and second barrier films120, 130 and the first and second bonding films 100, 110 is preferablyin a range of 1 through 1000 nm, and more preferably in a range of 2through 800 nm. By setting the average thickness of the first and secondbonding films 100, 110 to be within this range, it becomes possible tobond the first and second substrates 20, 30 more solidly to each otherwhile preventing the dimensional accuracy from being remarkablydegraded. In other words, if the average thickness becomes lower thanthe lower limit value, there is a possibility that sufficient bondingstrength fails to be obtained on the one hand, if the average thicknessbecomes higher then the upper limit value, the dimensional accuracymight be remarkably degraded on the other hand.

Further, if the average thickness falls within the range describedabove, a certain level of ability of following a shape can be provided.Therefore, even in the case in which, for example, unevenness exists onthe bonding surfaces of the first and second substrates 20, 30, it ispossible to make the first and second bonding films 100, 110 adhere soas to follow the shape of the unevenness although depending on theheight of the unevenness. As a result, the first and second bondingfilms 100, 110 can absorb the unevenness to ease the height of theunevenness caused on the surfaces thereof, thereby enhancing theadhesiveness therebetween.

Although such first and second barrier films 120, 130 and first andsecond bonding films 100, 110 can be manufactured by any method, such asa plasma polymerization method, various types of vapor depositionmethods including a CVD method and a PVD method, or various types ofliquid phase deposition methods, those manufactured by the plasmapolymerization method among these methods are preferable. According tothe plasma polymerization method, a dense and homogeneous film canefficiently be manufactured. Thus, the first and second bonding films100, 110 manufactured by the plasma polymerization method can bond thefirst and second substrates 20, 30 particularly solidly to each other.Further, in the first and second bonding films 100, 110 manufactured bythe plasma polymerization method, the activated state created byproviding the activation energy can be maintained for a relatively longperiod of time. Therefore, simplification and enhancement in efficiencyof the manufacturing process of the optical filter 10 can be achieved.

3. Modified of Manufacturing Optical Filter

3.1. Manufacturing Process of First Substrate 20

FIGS. 5A through 5C and 6A through 6C show a manufacturing process ofthe first substrate 20. Firstly, as shown in FIG. 5A, mirror polishingis performed on the both surfaces of a synthetic silica glass substrateto thereby manufacture the first substrate 20 with a thickness of 500μm.

Subsequently, on the both surfaces 20A, 20B of the first substrate 20, aCr film with a thickness of, for example, 50 nm is formed, then a masklayer (the same as mask layers 140, 141 shown in FIG. 7B althoughomitted in FIG. 5B) formed of an Au film with a thickness of 500 nm isformed thereon, then a resist (not shown) is applied to the surface ofthe mask layer on the side of one 20A of the surfaces, and then resistpatterning for forming a recessed section 22 for providing the firstopposed surface 20A1 to the one surface 20A is performed. Subsequently,the Au film corresponding to the opening section of the resist is etchedwith a compound liquid of iodine and potassium iodide, the Cr film isetched with ceric ammonium nitrate solution, and then the recessedsection 22 is etched by wet-etching with, for example, hydrofluoric acidsolution to have a depth of, for example, about 1.5 μm (see FIG. 5B).Subsequently, the resist and the mask layer are removed from the firstsubstrate 20.

Then, a mask layer is provided to the both surfaces 20A, 20B of thefirst substrate 20, then a resist (not shown) is applied to the surfaceof the mask layer of the one surface 20A, and then resist patterning forfurther providing the second and fourth opposed surfaces 20A2, 20A4 tothe surface 20A provided with the recessed section 22 is performed.Subsequently, the Au film and the Cr film in the opening section of theresist are etched, and then the one surface 20A is etched by wet-etchingwith, for example, hydrofluoric acid solution to have a depth of, forexample, about 1 μm (see FIG. 5C). Thus, the second and fourth opposedsurfaces 20A2, 20A4 are simultaneously provided to the opposed surface20A of the first substrate 20, and at the same time, the opposed surface20A not etched forms the third opposed surface 20A3. Subsequently, theresist and the mask layer are removed from the first substrate 20.

Then, an ITO film is deposited on the entire etched surface of the firstsubstrate 20 with a thickness of, for example, 0.1 μm using a sputteringmethod. A resist is applied to the surface of the ITO film, then resistpatterning is performed, then the ITO film is etched with a compoundliquid of, for example, nitric acid and hydrochloric acid, and thenresist is removed. Thus, the first electrode 60 is provided to thesecond opposed surface 20A2 of the first substrate 20, and the firstwiring layer 62 is provided to the fourth opposed surface 20A4 of thefirst substrate 20 (see FIG. 6A).

Then, resist patterning for forming an opening only in the area on thefirst substrate 20 where the first reflecting film 40 is formed isperformed, and then the reflecting film materials are deposited by asputtering method or an evaporation method. The first reflecting filmmaterials are stacked in the order of, for example, an SiO₂ layer with athickness of 50 nm, a TiO₂ layer with a thickness of 50 nm, and an Aglayer with a thickness of 50 nm from the side of the second substrate30. Subsequently, the first reflecting film materials are lifted off byremoving the resist, and the first reflecting film materials remain onlyin the area where the resist has the opening, thereby forming the firstreflecting film 40 (see FIG. 6B).

Then, resist patterning for forming an opening in each of the areas tobe provided with the first bonding film 100A and the first barrier film120 is performed, and then the plasma-polymerized film forming both ofthe bonding film and the barrier film is deposited by a plasma CVDmethod to have a thickness of, for example, 30 nm. As the primarymaterial of the plasma-polymerized film, polyorganosiloxane describedabove is preferably used. In the plasma polymerization, the frequency ofthe high frequency power applied between the pair of electrodes is in arange of 1 through 100 kHz, preferably in a range of 10 through 60 kHz,the inner pressure of the chamber is in a range of 1×10⁻⁵ through 10Torr, preferably in a range of 1×10⁻⁴ through 1 Torr (133.3×10⁻⁴ through133.3 Pa), the material gas flow rate is in a range of 5 through 200sccm, preferably in a range of 10 through 500 sccm, and the process timeis in a range of 1 through 10 minutes, preferably in a range of 4through 7 minutes.

Subsequently, the plasma-polymerized film is lifted off by removing theresist, thereby forming the first bonding film 100A and the firstbarrier film 120 (see FIG. 6C). Thus, the first substrate 20 iscompleted.

3.2. Manufacturing Process of Second Substrate 30

FIGS. 7A through 7D and 8A through 8D show a manufacturing process ofthe second substrate 30. Firstly, mirror polishing is performed on theboth surfaces of a synthetic silica glass substrate to therebymanufacture the second substrate 30 with a thickness of 200 μm (see FIG.7A).

Then, Cr films with a thickness of, for example, 50 nm are deposited onthe both surfaces 30A, 30B of the second substrate 30, and then masklayers 140, 142 each formed of an Au film and with a thickness of 500 nmare deposited thereon (see FIG. 7B).

Subsequently, a resist (not shown) is applied to the surface of the masklayer 140 of the second substrate 30, and then resist patterning forproviding the diaphragm section 32 (see FIG. 2) to one 30B of thesurfaces is performed. Subsequently, the Au film of the mask layer 140is etched with a compound liquid of iodine and potassium iodide, thenthe Cr film of the mask layer 140 is etched with ceric ammonium nitratesolution, thereby forming the mask layer 141 patterned (see FIG. 7C).

Then, the second substrate 30 is dipped in hydrofluoric acid solution tothereby etch the diaphragm section 32 as much as, for example, about 150μm (see FIG. 7D). The thickness of the diaphragm section 32 becomes, forexample, about 50 μm, and the thick-wall area including the reflectingfilm support section 34 remains with a thickness of 200 μm.

Subsequently, the resist and the mask layers 141, 142 attached to theboth surfaces 30A, 30B of the second substrate 30 are removed (see FIG.8A).

Then, an ITO film is deposited on the opposite surface 30A to the etchedsurface 30B of the second substrate 30 with a thickness of, for example,0.1 μm using a sputtering method. A resist is applied to the surface ofthe ITO film, then the resist patterning for the second electrode 70 andthe second wiring layer 72 is performed, and then the ITO film is etchedwith a compound liquid of nitric acid and hydrochloric acid.Subsequently, the resist is removed from the second substrate 30 (seeFIG. 8B).

Then, resist patterning for forming an opening only in the area wherethe second reflecting film 50 is formed is performed on the one surface30A of the second substrate 30 provided with the second electrode 70,and then the second reflecting film materials are deposited by asputtering method or an evaporation method. As an example of thedeposition, the second reflecting film materials are stacked in theorder of, for example, an SiO₂ layer with a thickness of 50 nm, a TiO₂layer with a thickness of 50 nm, and an Ag layer with a thickness of 50nm from the side of the second substrate 30. Subsequently, the secondreflecting film materials are lifted off by removing the resist, therebyforming the second reflecting film 50 (see FIG. 8C).

Then, resist patterning for forming an opening in each of the areas tobe provided with the second bonding film 110A and the second barrierfilm 130 is performed, and then the plasma-polymerized film forming bothof the bonding film and the barrier film is deposited by a plasma CVDmethod to have a thickness of, for example, 30 nm. As the primarymaterial of the plasma-polymerized film, polyorganosiloxane describedabove is preferably used. Subsequently, the plasma-polymerized film islifted off by removing the resist, thereby forming the second bondingfilm 110A and the second barrier film 130 (see FIG. 8D). Thus, thesecond substrate 30 is completed.

3.3. Bonding Process of First and Second Substrates

FIGS. 9 and 10 show the bonding process of the first and secondsubstrates 20, 30. FIG. 9 schematically shows a process for providingthe activation energy to the first and second bonding films 100A, 110Anot activated. There are various kinds of methods for providing theactivation energy to the first and second bonding films 100A, 110A, andtwo examples will be explained here.

One is the activation using ozone, and for example, an O₂ plasma processcan be cited. In the case of the O₂ plasma process, under the conditionsin which the O₂ flow rate is in a range of, for example, 20 through 40cc/min, the pressure is in a range of, for example, 20 through 35 Pa,the RF power is in a range of, for example, 150 through 250 W, the firstand second substrates 20, 30 are each processed for, for example, 10through 40 seconds in the plasma processing container.

The other is the activation using ultraviolet (UV) irradiation, in whicha UV light source having an emission wavelength range of 150 through 300nm, preferably 160 through 200 nm is used, and the ultraviolet ray isapplied to the first and second bonding films 100A, 110A not activatedwith a distance in a range of 3 through 3000 nm, preferably in a rangeof 10 through 1000 nm for 1 through 10 minutes. It is also possible, forexample, that the first and second substrates 20, 30 are stacked asshown in FIG. 9, and the ultraviolet ray is applied through either oneor both of the first and second substrates 20, 30 made of, for example,silica glass. Alternatively, it is also possible that the first andsecond substrates 20, 30 are separately processed, and the first andsecond bonding films 100A, 110A not activated is directly irradiatedwith the ultraviolet ray.

In this activation energy provision process, as described above, theelimination groups 303 are eliminated from the Si skeleton 301 of thefirst and second bonding films 100A, 110A not activated, and the activehands 304 are generated by the provision of the activation energy in thefirst and second substrates 100B, 110B activated. Further, in theactivation energy provision process, as described above, the first andsecond barrier films 120, 130 can protect the first and secondreflecting films 40, 50 from ozone or ultraviolet radiation.

After the provision of the activation energy, alignment of the first andsecond substrates 20, 30 is performed, and the first and secondsubstrates 20, 30 are overlapped each other as shown in FIG. 10, and theload is applied thereto. On this occasion, as described above, theactive hands (dangling bonds) 304 of the first and second bonding films100B, 110B provided with the activation energy are bonded to each otherto thereby solidly bond the first and second bonding films 100, 110 toeach other. Thus, bonding between the first and second substrates 20, 30is completed. Subsequently, the first electrode lead-out section 64shown in FIG. 1 and the second electrode lead-out section 74 forconnecting the second electrode 70 to an external device are formed,thereby completing the optical filter 10.

4. Analytical Instrument

FIG. 11 is a block diagram showing a schematic configuration of acolorimeter as an example of an analytical instrument according to anembodiment of the invention.

In FIG. 11, the colorimeter 200 is provided with a light source device202, a spectral measurement device 203, and a colorimetric controldevice 204. The colorimeter 200 emits, for example, a white light beamfrom the light source device 202 toward the test object A, and theninput the test target light beam, the light beam reflected by the testobject A, to the spectral measurement device 203. Subsequently, thecolorimeter 200 disperses the test target light beam with the spectralmeasurement device 203, and then spectral characteristics measurementfor measuring the intensity of each of the light beams with respectivewavelengths obtained by the dispersion is performed. In other words, thecolorimeter 200 makes the test target light beam as the light beamreflected by the test object A enter the optical filter (an etalon) 10,and then performs the spectral characteristics measurement for measuringthe intensity of the light beam transmitted through the etalon 10.Subsequently, the colorimetric control device 204 performs thecolorimetric process of the test object A, namely analyzes thewavelengths of the colored light beams included therein, and theproportions of the colored light beams, based on the spectralcharacteristics thus obtained.

The light source device 202 is provided with alight source 210 and aplurality of lenses 212 (one of the lenses is shown in FIG. 11), andemits a white light beam to the test object A. Further, the plurality oflenses 212 includes a collimator lens, and the light source device 202modifies the white light beam emitted from the light source 210 into aparallel light beam with the collimator lens, and emits it from theprojection lens not shown to the test object A.

As shown in FIG. 11, the spectral measurement device 203 is providedwith the etalon 10, a light receiving section 220 including lightreceiving elements, a drive circuit 230, and a control circuit section240. Further, the spectral measurement device 203 has an entranceoptical lens not shown disposed at a position opposed to the etalon 10,the entrance optical lens guiding the reflected light beam (the testtarget light beam) reflected by the test object A into the insidethereof.

The light receiving section 220 is composed of a plurality ofphotoelectric conversion elements (the light receiving elements), andgenerates an electric signal corresponding to the received lightintensity. Further, the light receiving section 220 is connected to thecontrol circuit section 240, and outputs the electric signal thusgenerated to the control circuit section 240 as a light receptionsignal. It should be noted that it is possible to constitute an opticalfilter module by integrating the etalon 10 and the light receivingsection (the light receiving elements) 220 as a unit.

The drive circuit 230 is connected to the first electrode 60 and thesecond electrode 70 of the etalon 10, and the control circuit section240. The drive circuit 230 applies the drive voltage between the firstelectrode 60 and the second electrode 70 based on the drive controlsignal input from the control circuit section 240 to thereby displacethe second substrate 30 to a predetermined displacement position. Thedrive voltage can be applied so that the desired electrical potentialdifference is caused between the first electrode 60 and the secondelectrode 70, and for example, it is also possible to apply apredetermined voltage to the first electrode 60 while setting the secondelectrode 70 to the ground potential. A direct-current voltage ispreferably used as the drive voltage.

The control circuit section 240 controls overall operations of thespectral measurement device 203. As shown in FIG. 11, the controlcircuit section 240 is mainly composed of, for example, a CPU 250 and astorage section 260. Further, the CPU 250 performs a spectralmeasurement process based on various programs and various data stored inthe storage section 260. The storage section 260 is configured includinga recording medium such as a memory or a hard disk drive, and stores thevarious programs and various data so as to be arbitrarily retrieved.

Here, the storage section 260 stores a voltage adjustment section 261, agap measurement section 262, alight intensity recognition section 263,and a measurement section 264 as a program. It should be noted that asdescribed above the gap measurement section 262 can be omitted.

Further, the storage section 260 stores voltage table data 265containing voltage values to be applied to the electrostatic actuator 80for controlling the spacing of the first gap G1 and the time periods,during which the respective voltage values are applied, in conjunctionwith each other.

The colorimetric control device 204 is connected to the spectralmeasurement device 203 and the light source device 202, and performs thecontrol of the light source device 202 and the colorimetric processbased on the spectral characteristics obtained by the spectralmeasurement device 203. As the colorimetric control device 204, ageneral-purpose personal computer, a handheld terminal, acolorimetric-dedicated computer, and so on can be used.

Further, as shown in FIG. 11, the colorimetric control device 204 isconfigured including a light source control section 272, a spectralcharacteristics obtaining section 270, a colorimetric processing section271, and so on.

The light source control section 272 is connected to the light sourcedevice 202. Further, the light source control section 272 outputs apredetermined control signal to the light source device 202 based on,for example, a setting input by the user to thereby make the lightsource device 202 emit a white light beam with a predeterminedbrightness.

The spectral characteristic obtaining section 270 is connected to thespectral measurement device 203, and obtains the spectralcharacteristics input from the spectral measurement device 203.

The colorimetric processing section 271 performs the colorimetricprocess for measuring the chromaticity of the test object A based on thespectral characteristics. For example, the colorimetric processingsection 271 performs a process of making a graph of the spectralcharacteristics obtained from the spectral measurement device 203, andthen outputting it to an output device such as a printer or a displaynot shown.

FIG. 12 is a flowchart showing the spectral measurement operation of thespectral measurement device 203. Firstly, the CPU 250 of the controlcircuit section 240 starts the voltage adjustment section 261, the lightintensity recognition section 263, and the measurement section 264.Further, the CPU 250 initializes a measurement count variable “n” (setn=0) as an initial state (step S1). It should be noted that themeasurement count variable n takes an integer value equal to or largerthan 0.

Subsequently, the measurement section 264 measures (step S2) theintensity of the light beam transmitted through the etalon 10 in theinitial state, namely the state in which no voltage is applied to theelectrostatic actuator 80. It should be noted that it is also possibleto previously measure the dimension of the first gap G1 in the initialstate, for example, at the time of manufacturing of the spectralmeasurement device and store it in the storage section 260. Then, themeasurement section 264 outputs the intensity of the transmitted lightbeam and the dimension of the first gap G1 in the initial state obtainedhere to the colorimetric control device 204.

Subsequently, the voltage adjustment section 261 retrieves (step S3) thevoltage table data 265 stored in the storage section 260. Further, thevoltage adjustment section 261 adds (step S4) “1” to the measurementcount variable n.

Subsequently, the voltage adjustment section 261 obtains (step S5) thevoltage data of the first and second segment electrodes 62, 64 and thevoltage application period data corresponding to the measurement countvariable n from the voltage table data 265. Then, the voltage adjustmentsection 261 outputs the drive control signal to the drive circuit 230 tothereby perform (step S6) the process of driving the electrostaticactuator 80 in accordance with the data of the voltage table data 265.

Further, the measurement section 264 performs (step S7) the spectralmeasurement process at the application time elapse timing. Specifically,the measurement section 264 makes the light intensity recognitionsection 263 measure the intensity of the transmitted light. Further, themeasurement section 264 performs the control of outputting the spectralmeasurement result, which includes the intensity of the transmittedlight beam thus measured and the wavelength of the transmitted lightbeam in conjunction with each other, to the colorimetric control device204. It should be noted that in the measurement of the light intensity,it is also possible to store the data of the light intensity of aplurality of times of measurement or all of the times of the measurementin the storage section 260, and then measure the light intensity of eachof the turns of the measurement in a lump after the data of the lightintensity of a plurality of times of measurement or all of the data ofthe light intensity has been obtained.

Subsequently, the CPU 250 determines (step S8) whether or not themeasurement count variable n reaches the maximum value N, and if itdetermines that the measurement count variable n is equal to N, itterminates the series of spectral measurement operation. In contrast, ifit is determined in the step S8 that the measurement count variable n issmaller than N, the CPU 250 returns to step S4 and performs the processof adding “1” to the measurement count variable n, and then repeats theprocess of the steps S5 through S8.

5. Optical Apparatus

FIG. 13 is a block diagram showing a schematic configuration of atransmitter of a wavelength division multiplexing system as an exampleof an optical apparatus according to an embodiment of the invention. Inthe wavelength division multiplexing (WDM) communication, using theproperty of the light that the signals with respective wavelengthsdifferent from each other do not interfere each other, by using aplurality of light signals with respective wavelengths different fromeach other in a single optical fiber in a multiplexed manner, it becomespossible to increase the data transmission quantity without expandingthe optical fiber lines.

In FIG. 13, a wavelength division multiplexing transmitter 300 has anoptical filter 10 to which a light beam from a light source 310 isinput, and a plurality of light beams with respective wavelengths λ0,λ1, λ2, . . . is transmitted through the optical filter 10. Transmissiondevices 311, 312, and 313 are provided corresponding to the respectivewavelengths. Optical pulse signals corresponding to a plurality ofchannels output from the transmission devices 311, 312, and 313 arecombined by a wavelength division multiplexing device 321 into onesignal, and then output to an optical fiber transmission channel 331.

The invention can also be applied to an optical code divisionmultiplexing (OCDM) transmitter in a similar manner. This is becausealthough in the OCDM the channels are discriminated by pattern matchingof encoded optical pulse signals, the optical pulses constituting theoptical pulse signals include light components with respectivewavelengths different from each other.

Although some embodiments are hereinabove explained, it should easily beunderstood by those skilled in the art that various modifications notsubstantially departing from the novel matters and the effects of theinvention are possible. Therefore, such modified examples should beincluded in the scope of the invention. For example, a term described atleast once with a different term having a broader sense or the samemeaning in the specification or the accompanying drawings can bereplaced with the different term in any part of the specification or theaccompanying drawings.

The entire disclosure of Japanese Patent Application No. 2010-057291,filed Mar. 15, 2010 is expressly incorporated by reference herein.

What is claimed is:
 1. A method of manufacturing an optical filtercomprising: (a) providing a first bonding film to a first substrateprovided with a first reflecting film capable of reflecting a light beamand transmitting a light beam with a specific wavelength; (b) providinga second bonding film to a second substrate provided with a secondreflecting film capable of reflecting a light beam and transmitting alight beam with a specific wavelength; (c) forming a first barrier filmadapted to cover a surface of the first reflecting film of the firstsubstrate to thereby protect the first reflecting film; (d) forming asecond barrier film adapted to cover a surface of the second reflectingfilm of the second substrate to thereby protect the second reflectingfilm; (e) providing activation energy by irradiating each of the firstand second bonding films using an ultraviolet ray or exposing each ofthe first and second bonding films to ozone gas; and (f) bonding thefirst and second bonding films activated to thereby bond the first andsecond substrates to each other, wherein step (c) is performed prior toproviding the activation energy to the first bonding film in step (e),step (d) is performed prior to providing the activation energy to thesecond bonding film in step (e), the first and second bonding films andthe first and second barrier films are each formed including an Siskeleton having a siloxane bond, and an elimination group connected tothe Si skeleton, step (e) includes (e1) forming a dangling bond byeliminating the elimination group from the Si skeleton in each of thefirst and second bonding films, and step (f) includes (f1) bonding thedangling bonds of the respective first and second bonding films, whichare activated, to each other.
 2. The method according to claim 1,wherein the first barrier film and the first bonding film are depositedwith the same material in the same process, and the second barrier filmand the second bonding film are deposited with the same material in thesame process.